1. Field of the Invention
The present invention relates to a shunt switch using MEMS (Micro Electro Mechanical Systems: micromachine), a semiconductor device, a module and an electronic device each of which includes the shunt switch.
2. Description of the Related Art
With a recent improvement in integration technology, technology for electronic devices to reduce their sizes and weights and achieve lower voltage operation, lower power consumption and higher frequency operation is advancing rapidly. In particular, in technology for mobile communication devices such as cellular phones, in addition to the above-described rigorous demands, higher performance is demanded, so as one of techniques for solving these conflicting issues, attention has been given to MEMS. The MEMS are systems in which a micro-mechanical element and an electronic circuit element are integrated by a silicon process technique, and in Japan, the MEMS are mostly called micromachine. Small and low-cost SoCs (Systems-on-a-chip) with higher performance are achievable by superior characteristics such as high precision processing of MEMS technology.
In the technology of mobile communication devices, various semiconductor devices using MEMS technology have been developed, and one of them is a switch for mechanically connecting and disconnecting a signal line which transmits a high-frequency signal. In switches for high frequency in related art, a shunt type switch in which a transmission line is connected to a ground through a shunt line in an OFF state as described in, for example, Japanese Unexamined Patent Application Publication No. 2003-264122 is used more widely than a series type switch in which a transmission line is physically disconnected in an OFF state.
For example, in a shunt switch in Japanese Unexamined Patent Application Publication No. 2003-264122, while a transmission line and a ground line are arranged on a substrate, a moving electrode as a shunt line is arranged above the substrate, and the transmission line is connected to a ground by bringing the moving electrode into contact with the transmission line and the ground line.